1. Field of the Invention
This invention generally relates to an actuator incorporated into a mouse or the like and used for, for example, a personal computer, and more particularly, to an actuator having a portion that moves on a plane with magnetic attraction.
2. Description of the Related Art
Conventionally, small-sized actuators including a portion that moves on a plane with magnetic attraction have been proposed. These actuators are expected to be a new type of device to transmit various pieces of information to an operator from a computer. For instance, the above-mentioned actuator can be incorporated into a mouse widely used with the personal computer. With respect to the mouse, the mouse has conventionally been used as an input device from the operator to the computer. However, in the case where the above-mentioned actuator is incorporated into the mouse, a signal emitted from the computer can be transmitted to the operator. That is to say, the conventional mouse can be utilized as one of machine-man interfaces.
Japanese Patent Application Publication No. 10-117470 (hereinafter referred to as Document 1) discloses a small-sized actuator that moves on the plane. This actuator includes a coil body and a magnet body. The coil body is composed of a large and small loop-shaped coils arranged on the plane. The magnet body is composed of four permanent magnets secured to a base plate and generates a magnetic flux to interlink with the respective loop-shaped coils. This actuator keeps the coil body and the magnet body in a parallel state, controls a relative movement, and moves the coil body or the magnet body on the plane with the use of the thrust force generated when the loop-shaped coils are conducted.
Document 1 discloses the actuator that moves the coil body or the magnet body on the plane. However, sufficient studies have not been conducted yet so that the user can use the actuator in a comfortable manner. This type of actuator is downsized and incorporated into an input device such as a mouse or controller. When the mouse is used, the current passes through the coil and moves the coil or magnet. If a movable range is set in advance, the input device might hit a movable limit (an edge of the movable range). The above-mentioned hitting might cause damage to the actuator, or a hitting sound will be unpleasant to hear. In addition, the actuator described in Document 1 does not have a function of returning to the original position after moving around. Therefore, if the current to the coil is cut off after the coil or magnet moves, the position of the actuator remains different from the original one. As described, the conventional actuator has drawbacks when the input device hits or returns to the original position, and it was not possible to use the input device having the conventional actuator in a comfortable manner.
Further, Document 1 discloses a type of actuator that moves on the plane only. With regard to the actuator incorporated into the mouse or the like, it is preferable to configure the mouse or the like multifunctionally in order to transmit as much information as possible. However, Document 1 does not describe this point.